# nusadua.dev

> Independent studio in Bali: tailored B2B software and independent research.

The studio models company processes in Python, tests the rules and compares possible improvements before building the software. Its work covers management finance, request approvals, shared team records, attributed history, contract review workflows, infrastructure and ongoing delivery and support. The website's interactive diagrams illustrate these capabilities; they are not measurements of client outcomes.

Research includes discrete geometry, combinatorics and learning experiments. The publication catalogue separates preprints, an open dataset, contributions to mathematical references and working notes. A preprint is not presented as a peer-reviewed publication. Exact results, certified lower bounds, heuristic models and open investigations retain their separate claim boundaries in the linked sources.

The primary website is https://nusadua.dev/. Public contact: studio@nusadua.dev. Meeting booking and the alternative contact request are available on the website. This file is a supplemental reading guide, not a crawler access policy; robots.txt remains the access-policy file.

## Studio and services

- [Software and company modelling](https://nusadua.dev/#software): Process models, software capabilities and the studio's approach.
- [Research and publications](https://nusadua.dev/#publications): Public bibliography, sequence contributions and the working-note library.
- [Contact and meeting booking](https://nusadua.dev/#contact): The current Google Calendar booking link and contact options.

## Published research records

- [Nineteen certified configurations, eighteen independent bounds for the no-four-coplanar problem in the cube, and what they do not establish (OEIS A280537)](https://doi.org/10.5281/zenodo.22272371): Preprint, 2026-09-03; version 3.4.
- [The error of the Guy-Kelly heuristic, measured against exact counts](https://doi.org/10.5281/zenodo.22063379): Preprint, 2026-08-23; version 1.9.
- [The direction spectrum of no-three-in-line solutions: a line model derives its shape, not its scale](https://doi.org/10.5281/zenodo.22278951): Preprint, 2026-09-03; version 1.1.
- [Witness configurations and lower bounds for the no-three-in-line problem in the n x n x n grid (OEIS A399138): a(8) >= 94, a(9) >= 116, a(10) >= 138, a(11) >= 164](https://doi.org/10.5281/zenodo.22271462): Dataset, 2026-09-03; version 1.1.
- [Certified exact values for the no-three-in-line problem in the three-dimensional grid](https://doi.org/10.5281/zenodo.22273425): Preprint, 2026-09-03; version 1.5.
- [Balanced orbit defects in half-turn-symmetric no-three-in-line configurations, with new 2n-point configurations for n = 36, 37, 39](https://doi.org/10.5281/zenodo.22064192): Preprint, 2026-08-23; version 1.3.
- [Extremal no-three-in-line subsets of a modular hyperbola in the Hall-Jackson-Sudbery-Wild window](https://doi.org/10.5281/zenodo.22275500): Preprint, 2026-09-03; version 1.18.
- [Pre-registered stakes against a tuned baseline: a one-day ledger of grokking interventions that mostly failed](https://doi.org/10.5281/zenodo.22196294): Preprint, 2026-08-31.

## Contributions to shared references

- [A399138: No three collinear points in a cubic grid](https://oeis.org/A399138): Sequence author: Aleksei Kudriashov.
- [A000755: Counting full-size planar no-three-in-line configurations](https://oeis.org/A000755): Aleksei Kudriashov contributed a(20) = 941580 to the existing sequence.
- [A280537: No four coplanar points in a cubic grid](https://oeis.org/A280537): Aleksei Kudriashov contributed the bound a(12) >= 31 and a witness configuration.
- [Achim Flammenkamp’s no-three-in-line archive](https://wwwhomes.uni-bielefeld.de/achim/no3in/readme.html): Credits Aleksei Kudriashov with 9 half-turn-symmetric configurations for grid sizes 33, 36, 37, 39 on 2026-08-17.

## Working notes

- [Every point, accounted for.](https://nusadua.dev/work/164-points.html)
- [Give the experiment time.](https://nusadua.dev/work/activation-and-normalisation.html)
- [When symmetry leaves a gap.](https://nusadua.dev/work/balanced-orbit-defects.html)
- [Can every vertex share one journey?](https://nusadua.dev/work/barnette.html)
- [The structure of what we learn.](https://nusadua.dev/work/data-structure.html)
- [Shape is not scale.](https://nusadua.dev/work/direction-spectrum.html)
- [Can a hard configuration split in two?](https://nusadua.dev/work/erdos-szekeres.html)
- [How wrong is a good heuristic?](https://nusadua.dev/work/guy-kelly-error.html)
- [First, fix the ruler.](https://nusadua.dev/work/honest-ruler.html)
- [Small proofs. Made to travel.](https://nusadua.dev/work/lemma-atelier.html)
- [A different way through.](https://nusadua.dev/work/lenses.html)
- [Modular hyperbolas](https://nusadua.dev/work/modular-hyperbolas.html)
- [No four in a plane.](https://nusadua.dev/work/no-four-coplanar.html)
- [No three on a line. In a cube.](https://nusadua.dev/work/no-three-in-line.html)
- [A rule learned. Then erased.](https://nusadua.dev/work/race-and-erasers.html)